1. Field
Embodiments of the invention relate to data management and, in particular, to systems and methods for reducing duplicate data in a computer system.
2. Description of the Related Art
With the increased reliance on computer systems to store critical information, the importance of protecting information has grown. As a result, certain storage systems receive an identification of a file to protect and then create one or more secondary copies, such as backup files, containing the contents of the file. These secondary copies can then later be used to restore the original data should anything happen to the original data.
In corporate environments, protecting information is generally part of a routine process that is performed for many computer systems within an organization. For example, a company might back up critical computing systems related to e-commerce such as databases, file servers, web servers, and so on as part of a daily, weekly, or monthly maintenance schedule. The company may also protect computing systems used by each of its employees, such as those used by an accounting department, marketing department, engineering department, and so forth.
Although each computer system contains certain unique information, many systems may contain very similar information. For example, although a computing system used by a marketing employee and a computing system used by an engineering employee will generally contain unique information created by each employee in the course of their work, both computing systems will likely have the same operating system installed, with thousands of identical or similar files used by the operating system. Similarly, both computing systems will likely have at least some similar application programs installed, such as a word processor, spreadsheet, Internet browser, and so on. Both systems may also have similar corporate information. For example, each employee may have an electronic copy of an employee manual distributed by the company. Information other than files may also be identical or similar between systems. For example, user settings and preferences may have similar default values on each system and application programs may contain similar templates on each system that are stored as application-specific information. As another example, several employees may have received a copy of the same email, and the email may be stored in each employee's electronic mailbox.
As a result of the amount of redundant information in an organization, secondary copies of an organization's information are often very large and can require the purchase of expensive storage devices and storage media. The restoration of data in the event of data loss is also slowed by the large size of the secondary copies. As the size of secondary copies increases, locating and restoring information requires more actions to be taken. For example, it may be necessary to search many tapes or other media to find the correct secondary copy. The great quantity of storage media, such as tapes, may mean that some secondary storage media has been moved offsite requiring that it first be retrieved before information can be recovered from it. Each of these factors increases the cost of protecting information and the time required to recover information in the event of data loss. Quick recovery of information is often critical to today's businesses, and any additional delay can affect business operations and customers' satisfaction with the business.